Light fixation for two-component epoxy resins

This means that the processing of the entire assembly can go ahead immediately. After an irradiation time of only five seconds at an intensity of 1000mW/cm², fixing strength of 1 N/mm² is achieved.

Reliable final curing including shadowed areas is the same as for regular two-component products at room temperature or speeded up, typically at 80°C for 60 minutes. The first option is likely more attractive to most users since it saves them investment and energy costs for heat curing, not to mention space on the production floor, and cycle and throughput rates are radically reduced. Since dispensing, joining, and light fixation take less than a minute, the next production step can begin much faster than the usual 15 to 90 minutes.

In addition, the new technology markedly simplifies logistics for users as products need not be transported and stored in a cooled state. A storage life of 12 months enhances production flexibility and enables the use of larger, and thus more cost-effective, containers.

“This new development is nothing short of a revolution,” said Karl Bitzer, Head of Product Management at DELO. “It combines the benefits of light curing with the strengths of two-component products. In the future, all users will need is a mixing system and lamps. Ovens, energy, and space on the shop floor can be saved, not to mention a huge amount of time.”

DELO-DUOPOX DB8989 provides good strength even when exposed to high temperatures and humidity. The adhesive thus achieves a tensile shear strength of 28 MPa on aluminium, and even during the ageing simulations required in the automotive industry, this value is maintained, for instance, after 500 hours' storage at 85°C and 85 % relative air humidity or at 150°C. As such, it can be used for structural bonding of, for example, rare earth magnets in electric motors. Thanks to low outgassing and shrinkage, the product is even suitable for opto-electronic applications in cameras.

Two-component adhesives are well-known for good strength, reliable curing at room temperature, good media resistance, and easy logistics. In the case of many high-volume applications, the time lapse before reaching initial strength was deemed a major disadvantage, until now.

In the future, DELO plans to develop several other two-component products with light fixation, including encapsulants for the sensor industry.